Safety apparatus for elevators



Jan. 13, 1959 R. "r. BERRY ETAL SAFETY APPARATUS FOR ELEVATORS 2 Sheets-Sheet 1 Filed Aug. 28, 1956 1N VENTORS Jan. 13, 1959 R. T. BERRY ETAL SAFETY APPARATUSFOR ELEVATORS 2 Sheets-Sheet 2 INVENTORS Filed Aug. 28, 1956 SAFETY APPARATUS FOR ELEVATORS Raymond '1. Berry, Arlington, Va., andGordon M. Hal-wood, Washington, D. C.

Application August 28, 1956, Serial N 0. 606,640

Claims (C1 18 7--2 9) This invention relates to new and useful improvements in safety apparatus for elevators, and in particular the invention concerns itself with safety apparatus which is responsive to the loading and possible over-loading of the elevator car.

The principal object of the invention is to prevent damageto the elevator equipment in general and breakage of hoist cables in particular, resulting from overloading of the car beyond its rated capacity.

This object is attained by the provision of safety.

apparatus which embodies, broadly, switch means for interrupting the power supply to the usual motor for actuating the hoist cables of the car so that the car cannot be movedwhen loaded beyond its rated limit.

An important feature of the invention resides in the pro-- vision of signalling means within the elevator car-for indicating to the. operator when the car is over-loaded.

Another important feature of the invention involves the provision of other signalling means within the elevator car for warning the operator when the car is loaded to nearly its rated capacity, so that over-loading. may be avoided.

Another feature of the invention resides in the pro-.

subjected by the force of inertia during, starting. and:

stopping. I

Another feature of the invention resides in arranging the safety apparatusin a compact assembly such asmay be conveniently installed. inelevator systems. of various types without the needfor heavy and cumbersome accessories or complex wiring.

Some of the. advantages ofthe invention lie-in its simplicity of construction, dependable operation, convenient accessibility for purposes of inspection or maintainance, and in its adaptability to economical manufacture, and installation.

With the foregoing more important objects and features in view and such other objects and features as may become apparent as this specification proceeds, the invention resides in the arrangement of parts and detailsof construction substantially as shown in the accompanying drawings, wherein like characters of reference are used to designate like parts and wherein:

Figure l is a top plan view of the invention per se, with the cover of the housing removed;

Figure 2 is a fragmentary sectional view on an enlarged scale, taken substantially in the plane of the line 2-2 in Figure 1;

Figure 3 is a fragmentary sectional view, taken sub stantially in the plane of the line 3.-3 in Figure 2;

Figure 4 is a wiring diagram of thecomponents of the invention;

Figure 5 is a fragmentary elevational view showing the "ice 2 inventionin conjunction. with elevator equipment,, the switch housing of the, apparatus being disposed at the top of the shaft,

Figure 6 isv a fragmentary 'elevational view on an enlarged scale, showing the operative connection between: the apparatus and the, anchorof one-of the hoist'cables;

Figure 7 is a fragmentary elevational view, similar-to, that shown in Figure 5 but illustrating the. switch housingasbeing disposed on the elevator car;

Figure 8- is a fragmentary elevational view on anene larged-scale, showing the-operative connection between; the apparatus andthecable anchor asarrangedin Figure;

7; and

Figure 9 is a fragmentary perspectivejviewofconnecting means used in'Figures 7 and 8.

Referring now to the accompanying drawings inl detail,v particularly to Figures 1-4thereof, the safety apparatus in accordance with the invention is designated generally by thereference numeralltl and embodiesin its construction a suitable, housing 11' provided with a removable; cover (not illustrated) and equipped inopposite side walls thereof'with a, pair of; coaxial bushings 12, 13 for a slid-;

ing rod 14. The latter projects at one end thereof from the housing andmay be provided with an enlarged head or cap 15, for a. purpose hereinafter to be, described. A- pair of normally open micro-switches 16, 17 are mounted ,within the housing ill by a suitable anglebarqlfiv to which they are secured by-the screws 19, the barv 18 itself being. fastened tothe bottomofthehousing by'the,

screws 20. The -switches-dlo, 17- are providedwith. clepressible' actuating stems 21, 22, respectively, and-it is to be noted that the position of the angle bar 18min the; housingis suchthat the stemsll, 22 of the switches are,

disposed below and in vertical alignment with the axis of the, rod M.

A. pair of collars 23, 24, provided with rounded or bevelled end faces 25, are secured at longitudinally spaced points to the rod M by suitable, set screws26 and are. operatively engageable with the actuating stems 21,- 22,

of the respective switches 16, 17. The setting of the, collars 23, 24 on the rod 14 is such with respect to thelongitudinal distance between the stems 21,, 22'that when;

the rod is in the position shown-in Figure 2, both stems are depressed, but when the rod is slidin the direction of the arrow 27, the collar 24} ridesoffthestem 22.and: releases that stem. before the collar-23 ridesoff-and re-. In this matter, sliding of therod 14 in the directionof the arrow 27 first closes the switch.-

leases the. stem. 21.

1'7 and then closesthe switch 16,

The rod l lis normally urged by a compression spring 28 to the position wherein the switches 16, 17 are closed, that is, in the direction of the arrow 27. The springr28 is positioned on therod 14 between the aforementioned; bushing 12 and an abutment collar 29 which is fastened to the rod by a setv screw 30. This facilitates proper pretensioning of'the spring and, of course, the'set'screws 26' permit adjustment of the collars 23, 24 on the rodld. the times and to assure closing of the switches 16, 17 at in themanner above stated.

The housing 11 also accommodates therein a relay switch assembly 31 including a solenoid 32and anarmature 33 having a'pairof switch members 34, ZiS'thereOn This ar-.

for opening and closing two. separate circuits. rangement is such that when thesolenoid 32 is not. active,

the circuit. through the switch member 34 is open while;

the circuit through the, switch member 35 is closed. On

the other hand, when the solenoid is energized, the circuitvential, construction and needs no further description.-

herein,v

Current to the apparatus, such as for example, volt 2,ses,ss2

current, is delivered through a suitable cable 36 which enters the housing 11 through a connector 37 provided in one of the housing side walls, the wire 38, 39 of the cable 36 being connected to a double socket receptacle 40 secured to the bottom of the housing. of this receptacle may be used for a test lamp, or the like, while the other socket accommodates a splug 41 at the end of a cable 42 having twin conductors 43, 44 therein. As will be noted, the conductors 43, 44 are in circuit with the respective wires 38, 39 when the plug 41 is inserted in the receptacle.

The apparatus also embodies in its construction a visual signalling device which is disposed remotely from the housing 11 and comprises a suitable box 45 equipped with signal lamps 46, 47 of different colors, such as for example, red and white, respectively. A multiconductor cable 48 extends from the box 45 through a connector 49 into the housing 11.

Finally, it will be noted that the housing 11 is also equipped with another connector 50 having a cable 51 extending through the same, the purpose of which will be hereinafter explained.

The wiring connections of the several components of the invention will be apparent from Figure 4, wherein it will be noted that one side 39, 44 of the 110 volt supply line is taken to one terminal 52 of the solenoid 32 of the relay switch 31, while the other side 38, 43 of the 110 volt supply line is taken to the switch member 34 of the relay switch. From the switch member 34 a connection is made by a wire 53 to the inlet terminal of the switch 16 and one of the outlet terminals of this switch is connected by a bridge 54 to the inlet terminal of the second switch 17. The switch 16 also has a second outlet terminal which is connected by a wire 55 to the remaining terminal 56 of the solenoid 32 and it should be mentioned at this point that the arrangement of the switch 16 is such that when the stem 21 thereof is depressed by the collar 23, circuit from the wire 53 to the wire 55 is open while circuit from the wire 53 to the bridge 54 is closed, whereby the switch 16 merely feeds the switch 17. However, when the stem 21 of the switch 16 is released by the collar 23, the circuit through the switch 16 to the switch 17 is opened and circuit from the wire 53 to the wire 55 is closed. The circuit through the switch 17 is open when the steam 22 thereof is depressed by the collar 24 and closed when the stem is released.

The outlet terminal of the switch 17 is connected by one of the wires 57 of the conductor 48 to the white signalling lamp 47 which in turn is bridged to the lamp 46 by a bridge 58 inside the box 45. The same side of the lamp 46 having the bridge 58 thereon is connected by another wire 59 of the conductor cable 48 to the terminal 52 of the solenoid 32, and the opposite side of the lamp 46 is connected by another wire 60 of the cable 48 to the terminal 56 of the solenoid.

The switch member 34 of the relay switch 31 is bridged by a pair of wires 61 extending through the cable 51 and connected to a switch 62 exteriorly of the housing 11. The cable 51 also contains a pair of conductors 63 of a separate power circuit, such as for example, 220 or 550 volts, connected to the switch member 35 of the relay switch 31.

With particular reference now to the accompanying Figures and 6 which illustrate one arrangement of installation of the invention, the elevator system is shown as including a car 64 movable upon guide rails 65 in an elevator shaft and counter-balanced by a suitable weight 66 which is similarly movable upon guide rails 67. The car 64 and the counter-weight 66 are operatively connected together by one or more hoist cables 68, passing N around pulleys 69 at the top of the car and 70 at the top of the counter-weight. For convenience of illustration only one of such hoist cables has been shown, and it will be noted that the same also passes over atraction pulley 71 at the top of the elevator shaft while both ends One of the sockets of the hoist cable are anchored as indicated at 72 to an overhead cross beam 73. As is customary in the art, this anchorage comprises a stem 74 connected to the end of the cable 68 by a coupling 75 and equipped with an enlarged head 76, the stem 74 passing slidably through the beam 73 and a compression spring 77 being provided on the stem between the beam and the head 76 so as to afford a resiliently yieldable anchorage for the cable.

The beam 73 also carries a drive motor 78 for the traction pulley 71 and an electrical control panel 79 for the entire apparatus.

When the invention is to be installed in an environment such as above outlined, the housing 11 is rigidly fastened, such as for example by a bracket 80 to one of the guide rails 65. In this manner the housing is firmly supported and does not yield such as it would if it were mounted on the beam 73 and the latter subjected to bowing or flexing under the weight of the car. The housing 11 is mounted so that the rod 14 projects downwardly therefrom and the. head 15 at the end of the rod 14 abuts the head 76 of the hoist cable anchor 72. When the car 64 is empty, the spring 77 is expanded and the head 76 retains the rod 14 in the position shown in Figure 2 wherein the stems 21, 22 of the switches 16, 17 are depressed by the collars 23, 24.

The cable 48 is arranged in the form of a drop cable between the housing 11 and the car 64 and the signalling box 45 is mounted inside the car, where the lamps 46, 47 thereof may be readily observed by the car operator. The cable 51 is extended from the housing 11 to the control panel 79, where the switch 62 is arranged to be opened and closed by a relay 81 which controls the flow of 220 or 550 volt current to the motor 78 in accordance with conventional practice. The wires 63 of the cable 51 are also connected to the relay 81, whereby to interrupt the power supply to the motor 78 when circuit through the switch member 35 is open.

The operation of the invention will be apparent from the following: When the car 64 is stationary, the relay 81 will cause the switch 62 to close, thus establishing circuit from the conductor 38 and through the conductors 43, 61 and 53 to the switch 16. With the car 64 empty or partly loaded, the position of the rod 14 is such that the collars 23, 24 depress the stems 21, 22 and sustain the switches 16, 17 in their open position. As explained in column 3, lines, 2246 of this specification, this will permit flow of current from the wire 53 to the switch 17, but since the latter is also held open by the collar 24, neither of the lamps 46, 47 will be energized.

However, when the car 64 is loaded, the increased weight thereof will cause compression of the anchor spring 77 and downward sliding of the stem 74. As a result, the rod 14 will also slide downwardly under the action of the spring 28 in keeping with the downward sliding movement of the stem 74, this sliding movement corresponding to the direction of the aforementioned arrow 27. When the load in the car reaches nearly its rated capacity, the collar 24 will release the stem 22 and cause closing of the switch 17. This, in turn, will permit current to flow through the wire 57 to the lamp 47, causing that lamp to emit white light and warn-the car operator that maximum loading has been nearly reached. In this manner, possible over-loading may be avoided. Current from the lamp 47 is returned through the wires 58, 59 and 44 to the wire 39. I

In the event the car is loaded beyond its rated capacity, further sliding of the rod 14 will cause the collar 23 to close the switch 16. In so doing, the flow of current to the switch 17 willbe discontinued, but current will flow through the wires 55 and 60 to energize the red lamp 46. This will notify the operator that overloading has occurred and simultaneously, current will also flow through the solenoid 32 to cause the armature 33 to open the 220 or 550 volt circuit through the switch member 35. As a result, the supply of power to the motor 78 willbe disgontinued and the operator will be unable to move the switches 16, 17 and preventing unnecessary energiza-' tion thereof by comparatively harmless bouncing motions of the car during starting and stopping.

The accompanying Figures 7-9 illustrate the invention installed in a somewhat diiferent elevator arrangement, wherein the hoist cable 82 is connected at one end thereof by the anchoring means 72 to a cross member 83 at the top of the car 64a. In such an arrangement the housing 11 is mounted inside or under the cross member 83 in an inverted position so that the rod 14 projects upwardly therefrom. The aforementioned head 15 of the rod 14 is substituted by a ring 84 which is threaded on the rod 14 and is locked'thereon by a nut 85. The ring 84 slidably receives therein a shaft 86 which is rigidly secured to and projects laterally from the stem 74 of the anchor 72, the attachment of the link or shaft 86 to the stem 74 being effected by a suitable clamp 87. Accordingly, when the spring 77 of the anchor 72 is compressed under load, the stem 74 will slide upwardly and cause a corresponding sliding of the rod 14 in the direction of the arrow 27, thus actuating the switches 16, 17 in the same manner as already described.

In this arrangement of the invention the cable 51 is taken to the usual door-operated safety switch 88 on the car, so as to interrupt power supply to the motor 78 either when the door of the car is open as is customary, or in the presence of over-loading. In addition, opening of the switch 88 is also arranged to close the actuating switch 62 of the invention, so that the invention is in operation only when the door is open for loading or unloading.

While in the foregoing there has been shown and described the preferred embodiment of the invention, various modifications may become apparent to those skilled in the art to which the invention relates. Accordingly, it is not desired to limit the invention to this disclosure and various modifications maybe resorted to, such as may lie within the spirit and scope of the appended claims.

What is claimed as new is:

l. The combination of an elevator including a car, a hoist cable for said car having a resiliently yieldable anchor at least at one end thereof, and a motor for actuating said cable, and a load-responsive safety apparatus comprising a normally closed relay switch for said motor, a signalling device provided in said car and including primary and secondary signalling members, a normally open primary switch in circuit with the primary signalling member of said signalling device, a normally open secondary switch in circuit with the secondary signalling member and with said relay switch, and means in operative engagement with the anchor of said cable for individually and successively closing the primary and secondary switches by a movement of the anchor in response to predetermined loading of said car.

2. The combination as defined in claim 1 together with means for energizing the primary and secondary switches only when said car is stationary.

3. The combination as defined in claim 1 together with a housing adapted to be rigidly mounted at a point adjacent said anchor and having said primary and secondary switches installed therein, said means comprising an actuating rod slidable in and projecting outwardly from said housing, actuating elements provided on said rod and operatively engaging said primary and secondary switches, and resilient means for urging said rod to a position wherein said primary and secondary switches are open, the projecting portion of said rod being in operative engagement with said anchor.

4. A load-responsive safety apparatus of the character described, comprising in combination, a housing, an actuating rod slidable in and projecting outwardly from said housing, a pair of spaced collars secured to said rod, primary and secondary micro-switches mounted in said housing and having depressible stems in operative engagement with the respective collars whereby the primary and secondary micro-switches may be individually and successively closed by the sliding of said rod, a normally closed relay switch mounted in said housing and adapted to be operatively connected to a load actuating motor, and a signalling device including primary and secondary signalling members in circuit with the respective primary and secondary micro-switches, said relay switch being in circuit with the secondary micro-switch, whereby the relay switch may be opened when the secondary signalling member is energized.

5. The combination of an elevator including a car,

. a motor operatively connected to said car for moving the same, a cable normally movable with said car at the same speed and in the same direction, said cable having a resiliently yieldable anchor, and a load responsive safety apparatus comprising a normally closed relay switch for said motor, a signalling device provided in said car and including primary and secondary signalling members, a normally open primary switch in circuit with the primary signalling member of said signalling device, a normally open secondary switch in circuit with the secondary signalling member and with said relay switch, and means in operative engagement with said cable for individually and successively closing the primary and secondary switches by a movement of said car relative to said cable in the presence of a predetermined load in the car.

Doolan July 7, 1953 Doolan July 7, 1953 

